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(No Model.)

G. AMBORN, Jr. & E.VD. OHAPLIN.

HAND VISE.

No. 282,033. Patented July 31,1883.

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UNITED STATES PATENT "OFFIC GEORGE AMBORN, JR, AND EDWIN D. CHAPLIN, OEPAWTUOKET, R. I.

HAND-VISE.

SPECIFICATION forming part of Letters Patent No. 282,033, dated July 31,1883.

Application filed June 13, 1883. (No model.)

.To all whom it may concern:

' Be it known that we, GEORGE AMBORN, J12, and EDWIN D. CHAPLIN, ofPawtucket, in the county of Providence and State of Rhode Island, haveinvented certain new and useful 7 greater pressure in closing the jawsof a vise upon an object, and at the same time retain the usualfacilities for opening and closing them quickly. This we accomplish bymeans of the compound or differential screw, hereinafter described, andwhich is illustrated in the accompanying drawings, in which- Figure 1shows a side elevation of ahand vise with the improvement. Fig. 2is avertical section of the same, except the screw, taken through the axisof the screw. Fig. 3 shows front and side views of the thumb-nut c. Fig.

4 shows front, and side views of the auxiliary nut f. Fig. 5 shows likeviews of the frictioncollar 9.

A represents a hand-vise,with a screw-bolt,

b, passing through the jaws in the usual way.

0 is a thumb or winged nut .fitted with a screw-thread to work on thescrew I). The hub of the thumb-nut c is lengthened out toward the vise,and has a screwthread cut on its outside of a finer pitch than thethread made on the screw 1), but running in the same direction-that isto say, if the thread 011 the screw bis right handed, the screw-threadon the hub of the thumb -nut 0 should also be a righthand one. Anauxiliary nut, f, milled on its edges, has a screw-thread made in it tofit on the threaded hub of the thumb-nut c. The side of this nut f thatis turned toward the jaw of the vise has a concave recess made in it, asseen in section in Fig. 2.

A collar, 9, is made to go between the auxiliary nut f and the jaw ofthe vise, the outer side of the collar being made wit-h a convexprojection fitting into the recess, before mentioned, in the nut f. Theother side of the collar g has one or more notches made in it to receivea projection (one or more) formed on the jaw of the vise or the notchesmay be made in the vise-jaw and the projections 011 the collar, ifpreferred. This collar g is for the purpose of increasing the frictionbetween the nut f and the jaw of the vise.

The operation of these devices is as follows:

WVhen the jaws of the vise are to be opened or closed quickly, orwithout regard to the pressure exerted, the thumb-nut cis turned in theproper direction, carrying with it the auxiliary nut f, by reason of thefriction of that nut on its screw, and while there is no resistance tothe closing of the jaws but that of the usual spring; but if thatfriction is not sufficient to move the nut f, the thumb and finger 011the thumb-nut may be extended over to reach the milled edge of the nut fand turn it with the other nut. hen the jaws begin to pinch on an objectbetween them, the

friction between the collar 9 and the recess inthe nut f will beincreased by the pressure, and the nut f will be held stationary, sothat the thumb-nut 0 will screw into it, and the effect will be that ifthe screw 2) has a thread of sixteen to the inch and the hub of thethumb-nut c has a thread of eighteen to the inch, while one turn of thethumb-nut will advance it on the screw 6 one sixteenth of an inch, themilled nut f will fall back one eighteenth of an inch, and thedifference between the two-0ne one-hundred-and-forty-fourth of an inchwill represent the actual movement of the jaws of the vise toward eachother. The ratio of pressure produced being inversely as the differencebetween the two movements, it follows that the jaws will be closed witha force of one hundred and forty-four to sixteenthat is to say, withnine times the power, minus the friction of the nut f, that would beexerted in using the screw b and thumb-nut c in the usual way.

Ve have here represented our improvement as applied to a hand-vise; butit is equally applicable to bench-vises and in vises having a paralleljaw movement. 'The collar -may be dispensed with, and the convexprojection on it formed on the jaw of the vise instead.

Having thus described our improvement,

what We claim as our invention, and desire to of the screw 1), thumb-nutc, auxiliary nut secure by Letters Patent, is p 1. The eon1bination,withthe jaws of a vise, of the screw 1), thumb -nut 0 and auxiliary nut f,constructed and operating substantially as herein described, and for thepurpose set forth.

2. The CO1lll)illittlOll,\"lth the jaws of a vise,

and friction-collar g, substantially as herein de 10 scribed, and forthe purpose specified.

- GEORGE AMBORN, J R.

EDWIN D. OHAPL] N.

\Vitnesses:

CHARLES H. BLooDGoon, JAMES S. ORooK,

